Counter Electrode For Dye-sensitized Solar Cells Research Articles

Designing highly effective mesoporous Carbon-based counter electrodes for liquid Electrolyte-based and Quasi-solid Dye-sensitized solar cells

In this study, nitrogen-doped mesoporous carbon (NMC) and boron-doped mesoporous carbon (BMC) are synthesized and used as Pt-free counter electrode (CE) materials for dye-sensitized solar cells (DSCs). The optimized NMC and BMC CEs exhibit significantly higher catalytic activities than the pristine mesoporous carbon (MC). The I-/I3- in acetonitrile liquid electrolyte-based DSCs have power conversion efficiencies (PCE) of 7.20% with the NMC CE and 7.15% with the BMC CE, which are significantly higher than that obtained using the MC CE (5.88%). This is attributed to the improved effective catalytic active sites and the enhanced electrical conductivities of the NMC and BMC CEs. When Pt with trace amounts (0.1 wt%) is loaded on NMC, the liquid DSCs using Pt/NMC composite CEs yield PCE values of 8.31% and 9.92%, respectively, under 1.0 Sun and 0.1 Sun illumination. The Pt/NMC CE is further employed in quasi-solid DSCs, which also give a high PCE of 8.15% under 1.0 Sun illumination. A flexible Pt/NMC CE is also prepared on indium tin oxide-polyethylene naphthalate (ITO-PEN) substrate, and the generated liquid DSCs show a PCE of 6.92%. This work provides a feasible path to enhance the catalytic activity of the MC CE in DSCs.

Preparation of CoNi@CN composites based on metal-organic framework materials as high efficiency counter electrode materials for dye-sensitized solar cells

In this paper, Co-based metal organic framework mixtures (MOFs) stuff are used as self-sustain templates to prepare CoNi alloys and N-codop porous carbon composites (CoNi@CN) by one-step calcination and ion exchange methods and apply to the study of the counter electrode (CE) of dye-sensitized solar cells (DSSCs). CoNi@CN retains a large specific surface area, high porosity and abundant unsaturated sites of MOFs, and the conductivity and catalytic activity of porous carbon are improved by the introduction of CoNi alloy and N. At the same time, the nitrogen-doped porous carbon protects the CoNi alloy from corrosion of the electrolyte and ensures the stability of the material. CoNi@CN is used in DSSCs for catalytic reduction of I3- exhibits the photoelectric conversion efficiency of 8.85%, that is overtop the exhibited by Pt CE under the equal conditions. Therefore, CoNi@CN composites are prepared based on MOFs are expected to instead of Pt as DSSCs CE materials because of their excellent optoelectronic properties and inexpensive.

Facile and functional synthesis of Ni0.85Se/Carbon nanospheres with hollow structure as counter electrodes of DSSCs

• Hollow Ni 0.85 Se/C nanospheres were synthesized by one-pot solvothermal method. • The resultant Ni 0.85 Se/C displays excellent electrochemical properties. • As CE in DSSC, the Ni 0.85 Se/C exhibits superior photoelectric performance to Pt. Dye-sensitized solar cells (DSSCs), which can make efficient use of solar energy, have attracted extensive attention worldwide. Counter electrodes (CEs) of DSSCs play an essential role in controlling I 3 - reduction, thus determining electrocatalytic activity. Accordingly, a facile solvothermal approach was utilized to synthesize Ni 0.85 Se nanospheres with the existence of glucose as carbon source (Ni 0.85 Se/C), serving as CEs. Compared with the unsupported Ni 0.85 Se, the Ni 0.85 Se/C nanospheres exhibited superior electrochemical properties owing to the addition of carbon from glucose and existence of hollow as well as mesoporous structures, even outperforming those of the precious platinum electrode. The overall power conversion efficiency of the DSSC with the Ni 0.85 Se/C CE attained 9.39%, exceeding that with the Ni 0.85 Se (8.47%) and platinum CEs (8.77%).

The modified W2C@C composites derived from the polyoxotungstate-based organic complexes assisted by pyrrole for efficient counter electrode in dye-sensitized solar cells

The modification and doping on the surface of transition metal compounds (TMCs) substitute for conventional Pt as counter electrode (CEs) catalysts that are a distinguishing route to reduce the cost and improve the power conversion efficiencies (PCE) of dye-sensitized solar cells (DSSCs). In this study, polyoxotungstate (H3PW12O40)-based organic complex assisted by different amounts pyrrole as precursor to prepare W-based carbide. Exploiting four different W2C@C composites derived from the determined concentration co-precursor with pyrrole amounts of 0.05, 0.10, 0.15 and 0.20 mL under high-purity N2 flow at the temperature 800 °C. The effects of different amounts pyrrole on the catalytic activity of as-prepared W2C@C composites were investigated by corresponding electrochemical experiments. As indicated from the results, the W2C@C composites by the additional pyrrole as an carbon source and nitrogen source in the pyrolysis process that can improve the uniformity of particle dispersion, promote the number of active sites, and provide more dispersed voids, and then achieved PCEs of 6.28, 6.76, 7.08 and 6.34% for iodide redox couple regeneration in the assembled DSSCs, respectively, suggesting a potential competent substitutes for the noble metal CEs in DSSCs.

Dye-sensitized solar cell using nickel sulfide-reduced graphene oxide counter electrode: Effect of sulphur content

The influence on sulphur content in term of thiourea (TU) concentration on the properties of nickel sulphide (NiS)-reduced graphene oxide (rGO) has been reported in this paper. The effect of sulphur content on the performance of dye-sensitized solar cell (DSSC) using NiS-rGO counter electrode (CE) has also been investigated. The source of sulphur is TU. The sample has been prepared via modified Hummers’s method assisted with spin coating technique. The cell using NiS-rGO CE prepared with 1.20 M TU yielded the highest power conversion efficiency (η) of 1.42%. This is due to this cell has the lowest series resistance (Rb) and charge transfer resistance at the interface of NiS-rGO CE/electrolyte (Rct) with the value of 0.44 and 4.09 Ω, respectively. It is also due to the sample with 1.20 M TU owns the highest reduction current (J). The finding of this work reveals that NiS-rGO is able to substitute platinum as CE for DSSC.

Screen-printed carbon black/SiO2 composite counter electrodes for dye-sensitized solar cells

Platinum (Pt)-based counter electrodes (CEs) are promising electrocatalysts for dye-sensitized solar cells (DSSCs). However, replacing the expensive Pt with low-cost materials and comparable catalytic activity still a big challenge. Here, we prepared CB-SiO2 composites by blending various weights of SiO2 (1, 3, and 5 wt%) with carbon black (CB), followed by screen printed onto the FTO substrate to utilized as CEs for DSSCs. In comparison with pure CB, CB-SiO2 composite CEs showed higher transferability and higher electrocatalytic activity toward I3-/I- redox couple. Among all, CB-SiO2-1% composite CE with 4 µm showed the best catalytic performance, and the related DSSC showed a power conversion efficiency of 6.38%. Increasing the CE thickness significantly enhances the catalytic ability and the total performance of the assembled devices, whereas the power conversion efficiency of the DSSC with CB-SiO2-1% composite CE in 8 µm thick was 7.99%, which is close to that achieved by Pt-based device under the same conditions.

Effect of thickness on charge transfer properties of conductive polymer based PEDOT counter electrodes in DSSC

Poly(3,4-propylenedioxythiophene (PEDOT) counter electrodes are considered to be one of the most promising alternatives to expensive Pt-based counter electrodes in dye sensitized solar cells (DSSC). In the present study, we prepared PEDOT counter electrodes with various thicknesses through scalable electropolymerization technique using a nontoxic mixture of sodium dodecyl sulfate (SDC) in water medium, which provides the opportunity for scale up and commercialization. The time scale for electropolymerization was varied systematically to tune the thickness and uniformity of PEDOT film. The PEDOT films and their interaction with conventional iodide/triiodide​ (I−/I3−) electrolyte was studied using various electrical and optical characterization techniques. The catalytic activity of porous PEDOT films were found to be decreasing with an increase in thickness. DSSCs fabricated using PEDOT counter electrodes having lower thickness of 33 nm (deposited with 5 s polymerization time) showed superior power conversion efficiency of 10.39%, followed by PEDOT counter electrodes having 65 nm and 120 nm thickness deposited with polymerization time of 10 s and 15 s delivering power conversion efficiencies of 8.11% and 7.45% respectively. Electrochemical Impedance Spectroscopy (EIS) was used to investigate the role of variation in PEDOT thickness with various charge transfer processes at the electrolyte/counter electrode interface influencing PV performance.

Enhanced efficiency of DSSC by lyophilized tin-doped molybdenum sulfide as counter electrode

The influence of lyophilization on the electrochemical properties of hydrothermally synthesized tin (Sn) doped molybdenum sulfide (MoS2) nanostructures are investigated thoroughly. The lyophilized tin doped MoS2 used as counter electrode (CE) in dye-sensitized solar cells (DSSCs) showed high efficiency and better stability. Power conversion efficiency (PCE) of 7.14% is achieved using lyophilized 2.5% Sn-doped MoS2 as CE in DSSCs, which is much higher than devices made of CE comprising oven air annealed samples (5.74%). The major enhancement of PCE is due to the large surface area of Sn-doped lyophilized MoS2 nanostructures as well as the high electrocatalytic activity of MoS2 towards reduction reaction, which are observed from BET, CV and EIS measurements. Sequential CV scanning further showed the high electrochemical stability of the Sn-doped MoS2 nanostructures. This indicates the useful application of lyophilizer technique to produce various other metal sulfide nanostructures to increase the porosity and overall surface area of the materials for optimum device performance.

Low cost, platinum free counter electrode with reduced graphene oxide and polyaniline embedded SnO2 for efficient dye sensitized solar cells

A composite consisting of Reduced Graphene Oxide (RGO), Tin Oxide (SnO2) nanoparticles and Polyaniline (PANI) conducting polymer was studied as a potential counter electrode material for Dye Sensitized Solar Cells (DSSCs). This RGO/SnO2/PANI composite CE was fabricated by spray method and used as an alternative to Platinum (Pt) counter electrode (CE). In the fabrication of RGO/SnO2/PANI composite CEs, several optimizations were carried out to obtain the optimum RGO sintering temperature and the optimum amounts of RGO, SnO2 and PANI. The photovoltaic performance of the DSSCs based on the newly prepared CEs was studied by using I-V measurements. The efficiency of the DSSC with the CE with optimized RGO/SnO2/PANI composition having 9.8 μm thickness was 7.92% under the 100 mW cm−2 (1.5AM) light illumination. After the TiCl4 treated TiO2 photoanode was used, the maximum power conversion efficiency of the DSSC based on the RGO/SnO2/PANI composite CE was increased to 8.68%, which corresponds to an impressive 94% of the efficiency of 9.22% obtained for the control DSSC made with Pt CE and TiCl4 treated photoanode measured under same light illumination. These composite CEs were characterized by X-ray diffraction, Raman spectra, FTIR spectra, SEM and TEM. Cyclic voltammetry (CV) analysis showed the excellent electro-catalytic activity of the composite CE. With high energy conversion efficiency and improved charge-transfer process of DSSCs in combination with simple preparation and relatively low-cost technique, the RGO/SnO2/PANI composite electrode demonstrates the beneficial use of this novel composite material as CEs in DSSCs.

Large-scale synthesis of ultra-long sodium doped MoS2 nanotubes with high electrocatalytic activity

Large-scale production of high-quality molybdenum disulfide (MoS2) nanotubes is important due to their special structure and inherent properties. In this paper, we reported a low-cost approach to synthesize ultra-long Na doped MoS2 nanotubes on a large-scale by sulfurizing the precursors which produced by a hydrothermal method. Sodium chloride (NaCl) and ammonium molybdate solution are stirring in a heated water bath to prepare these precursors. Then Na doped MoS2 nanotubes are obtained by vapor-phase sulfurization using sulfur powder as S source. Transmission electron microscopy (TEM) images, X-ray diffraction (XRD) pattern, Raman spectra and X-ray photoelectron spectroscopy (XPS) prove the crystal structure of Na doped MoS2 with elemental composition of NaxMoS2 (x = 0.38–0.44). The morphology of the samples shows pure high-quality Na doped MoS2 nanotubes with length ranging from 100 to 300 µm. When used as the counter electrode (CE) of dye-sensitized solar cells (DSSCs), these nanotubes have excellent electrocatalytic activity. A power conversion efficiency of 5.85% is recorded in these solar cells, which is near that of the referenced Pt counter electrodes. This makes these nanotubes are ideal CEs of DSSCs. So this method is a simple and convenient approach to synthesize transition metal dichalcogenides (TMDs) nanotubes on a large scale.

Dual heteroatom-doped reduced graphene oxide and its application in dye-sensitized solar cells

The quick reduction and regeneration of the electrolyte (triiodide/iodide redox couple, I3−/I−) is one of the main issues in dye-sensitized solar cells (DSSCs). The well-known platinum counter electrodes (CEs) that facilitate electrolyte reduction and regeneration are very expensive; hence, low-cost and efficient CEs are in demand to substitute the platinum CEs. Herein, we report the hydrothermal synthesis of single (boron or nitrogen) and dual (boron/nitrogen mixture) heteroatom-doped reduced graphene oxide (rGO) and their comparison as CEs in DSSCs. The photovoltaic, electrochemical and conductivity properties were investigated. Dual heteroatom-doped rGO demonstrated a relatively large surface area and enhanced electrical conductivity (161.51 m2 g−1 and 22.07 S cm−1, respectively) when compared to graphene oxide (GO), rGO and single heteroatom-doped rGO. The amount of boron- and nitrogen-doping, including their configuration, played a crucial role in the catalytic activity. The presence of pyridinic-N and pyrrolic-N in single and dual heteroatom-doped rGO promoted a triiodide reduction reaction, which shifted the redox potential, relative to GO and rGO. The BN-rGO-3 CE yielded a relatively higher PCE of 2.97%, further enhanced to 4.13% when the BN-rGO-3 CE was used in conjunction with polyaniline as a binder. Therefore, this showed that dual heteroatom-doped rGO CEs enhanced the PCE of the DSSCs due to the synergetic effect, doping configuration and higher doping levels. Thus, the present work provides a facile and productive strategy for configuring the dual heteroatom-doped graphene CE materials with high electrocatalytic activity for energy conversion devices.

Efficient Iron Phosphide Catalyst as a Counter Electrode in Dye-Sensitized Solar Cells

Developing an efficient material as a counter electrode (CE) with excellent catalytic activity, intrinsic stability, and low cost is essential for the commercial application of dye-sensitized solar cells (DSSCs). Transition metal phosphides have been demonstrated as outstanding multifunctional catalysts in a broad range of energy conversion technologies. Here, we exploited different phases of iron phosphide as CEs in DSSCs with an I–/I3–-based electrolyte. Solvothermal synthesis using a triphenylphosphine precursor as a phosphorus source allows to grow a Fe2P phase at 300 °C and a FeP phase at 350 °C. The obtained iron phosphide catalysts were coated on fluorine-doped tin oxide substrates and heat-treated at 450 °C under an inert gas atmosphere. The solar-to-current conversion efficiency of the solar cells assembled with the Fe2P material reached 3.96 ± 0.06%, which is comparable to the device assembled with a platinum (Pt) CE. DFT calculations support the experimental observations and explain the fundamental origin behind the improved performance of Fe2P compared to FeP. These results indicate that the Fe2P catalyst exhibits excellent performance along with desired stability to be deployed as an efficient Pt-free alternative in DSSCs.

Enhanced electrocatalytic activity in dye-sensitized solar cells via interface coupling of the CoFe2O4/Co3Fe7 heterostructure

The DSSC assembled with CoFe/CFO CE exhibits a higher power conversion efficiency (8.54%), which surpasses that of conventional Pt (7.70%). Such excellent performance can be ascribed to the unique interfacial structural optimization and intimate interface coupling synergies. The original core-shell layer enriches the active sites, and further structural integration improves the interface, increasing the conductivity while synergistically accelerating the catalytic activity. • Synthesis of CoFe 2 O 4 /Co 3 Fe 7 hybrids by hydrothermal and impregnation methods. • Structural integration and multi-component synergy maximize catalytic activity. • DSSC based on CoFe 2 O 4 /Co 3 Fe 7 CE exhibited higher PCE (8.54%) than Pt (7.70%). The exploitation of high-efficient yet non-precious counter electrode (CE) materials is of great significance for practical applications of dye-sensitized solar cells (DSSCs). Herein, Co 3 Fe 7 alloy anchored on the porous core-shell CoFe 2 O 4 composites (CoFe 2 O 4 /Co 3 Fe 7 ) were successfully manufactured as a counter electrode for DSSC. The detailed electrochemical measurements verified that the introduction of Co 3 Fe 7 alloys modifies the original core-shell structure, contributing to enhance electrical conductivity and promote interfacial electron transfer. While the porous structure increases the potential for exposing active sites and accelerates the diffusion of iodide ions. Moreover, the formation of hetero-junction facilitates the generation of active facet sharing and multi-component synergy, thus prominently boosting the reduction of triiodide and accelerating reaction kinetics. As a consequence, DSSCs structured with CoFe 2 O 4 /Co 3 Fe 7 -modified CEs achieve a satisfactory power conversion efficiency (PCE) of 8.54%, which surpasses that of conventional platinum (7.70%). Meanwhile, the stability of CoFe 2 O 4 /Co 3 Fe 7 CE is also enhanced than noble metals platinum. This work highlights that the heterogeneous CoFe 2 O 4 /Co 3 Fe 7 with a rich interface can effectively stimulate the catalytic activity of reducing triiodide to enhance the performance of the solar cell. This strategy also paves the way for enhancing material activity in the field of energy storage and conversion.

A strategy of adopted Co4S3/Co2P2O7 composite grew on carbon paper to enhance the efficient of dye-sensitized solar cells

Metal phosphates have shown good hydrogen evolution reaction catalytic ability, but as counter electrode (CE) materials they are rarely used in dye-sensitized solar cell (DSSC). A strategy that introduction of Co2P2O7 as a “collaborator” to improve the catalytic performance of Co4S3 for the DSSC. The Co4S3/Co2P2O7 film grew on carbon paper (CP) was synthesized by using a hydrothermal route and vapor deposition method, and served as platinum-free (Pt-free) CE for DSSC. The composite materials of Co4S3/Co2P2O7 has many advantages of unique spherical morphology, large special surface area, more active sites and fast reaction kinetics for the reduction of I−/I3−. Under optimal conditions, a DSSC based on the Co4S3/Co2P2O7/CP CE achieves a high power conversion efficiency of 8.99%, which is comparable to that of the Pt (7.49%) and CoS1.097/CP (8.18%) CEs. The results indicate that the Co4S3/Co2P2O7/CP CE with the advantages of efficient and facile synthesis is a promising alternative to the expensive Pt CE for the DSSCs in the future.

Cu2ZnSnS4 thin film as a counter electrode in zinc stannate-based dye-sensitized solar cells

In this study, we deposited Cu2ZnSnS4 (CZTS) thin films with various thicknesses using electrodeposition and sputtering methods to exploit them as counter electrodes (CEs) in Zn2SnO4 -based dye-sensitized solar cells (DSSCs). The ternary Zn2SnO4 compound with wide bandgap energy, large corrosive resistivity, high electron mobility, and an appropriate conduction band edge position concerning the dye molecules (N719) can be an outstanding alternative for photoanode besides CZTS CE in DSSCs. On the other hand, CZTS is an impressive candidate as a CE material, but its electrocatalytic activity for the recovery of ionic species can be different depending on the synthesis process. Our results indicated the creation of porous morphology in the solution-based deposited films, which yields higher electrocatalytic activity in the CE performance in comparison with the physical deposition method, resulting in short circuit current densities of 9.77 and 8.40 mA cm−2 and open-circuit voltages of 633 and 583 mV for the DSSCs prepared by the respective techniques. The large active area and highly crystallized CZTS films, prepared by the electrodeposition method, led to an around 50% efficiency improvement compared to the widely used, more expensive platinum.

Recent Advances on Pt-Free Electro-Catalysts for Dye-Sensitized Solar Cells.

Since Prof. Grätzel and co-workers achieved breakthrough progress on dye-sensitized solar cells (DSSCs) in 1991, DSSCs have been extensively investigated and wildly developed as a potential renewable power source in the last two decades due to their low cost, low energy-intensive processing, and high roll-to-roll compatibility. During this period, the highest efficiency recorded for DSSC under ideal solar light (AM 1.5G, 100 mW cm−2) has increased from ~7% to ~14.3%. For the practical use of solar cells, the performance of photovoltaic devices in several conditions with weak light irradiation (e.g., indoor) or various light incident angles are also an important item. Accordingly, DSSCs exhibit high competitiveness in solar cell markets because their performances are less affected by the light intensity and are less sensitive to the light incident angle. However, the most used catalyst in the counter electrode (CE) of a typical DSSC is platinum (Pt), which is an expensive noble metal and is rare on earth. To further reduce the cost of the fabrication of DSSCs on the industrial scale, it is better to develop Pt-free electro-catalysts for the CEs of DSSCs, such as transition metallic compounds, conducting polymers, carbonaceous materials, and their composites. In this article, we will provide a short review on the Pt-free electro-catalyst CEs of DSSCs with superior cell compared to Pt CEs; additionally, those selected reports were published within the past 5 years.

Ni2+ enriched carbon nanotubes nanohybrids based non-platinum counter electrodes for dye sensitized solar cells

The development of competent substitutes for Pt counter electrode (CE), possessing excellent electrocatalytic activity, stability, and ready availability, is a key issue to materialize the long-term stability and economical large-scale industrial production of future generation dye sensitized solar cells (DSSCs). In the present work, a cost effective and solution processable hydrothermal technique has been utilized to synthesize Ni2+ enriched nanohybrids of nickel oxide (NiO) and nickel sulfide (Ni3S2) nanoparticles with multi-walled carbon nanotubes (MWCNTs) as CE in DSSCs. NiO/MWCNTs nanohybrids showed superior electrocatalytic behaviour among MWCNTs, NiO, Ni3S2, nanohybrids, and Pt. The nanohybrids containing aligned network MWCNTs exhibited good electrical conductivity, high specific surface area and better stability. These nanohybrids have been further employed as CE in DSSCs and observed higher Power Conversion Efficiency (PCE) for NiO/MWCNTs nanohybrids CE (3.80%) among others and is almost comparable to that of Pt based DSSC (3.90%). It has been explained on the basis of Ni2+content present in the nanohybrids. The higher content of Ni2+species provides a greater number of active sites representing higher electrocatalytic activity that would further productively catalyze the reactions occurring at CE/electrolyte interface in DSSCs.

Enhanced properties of low-cost carbon black-graphite counter electrode in DSSC by incorporating binders

Carbon-based counter electrodes of dye-sensitized solar cells (DSSCs) such as carbon black-graphite composite (CB/Gr) have received unprecedented interest in recent years due to their ease of fabrication, good corrosion resistance, and low cost compared to platinum (Pt) electrodes. However, the poor surface adherence between the carbon counter electrodes (CE) and FTO substrate, low surface area, and poor inter-particle connection between the carbon materials have consistently become a major challenge. In order to overcome these issues, we have fabricated CB/Gr by incorporating binders of titanium (IV) isopropoxide (TTIP), and zirconium (IV) dioxide (ZrO2) as the counter electrodes for the DSSC. The performance of the CE is characterized by four-point probe conductivity measurement, scanning electron microscopy (SEM) and energy dispersive X-ray (EDX), X-ray photoelectron spectroscopy (XPS), electrochemical impedance spectroscopy (EIS), and current density voltage (J-V) characteristics. The results revealed that incorporating binders to the CB/Gr has improved the series resistance (RS) and charge transfer resistance (RCT), which enhances the short-circuit current density (JSC), fill factor (FF), and the power conversion efficiency (PCE) of the device. The TTIP binder in CB/Gr CE exhibited superior performance in DSSC is largely attributed to the formation of TiO2 in situ with small particle size of about 100 nm, leading to enhanced intimate contact between the carbon materials, high surface area, and better surface adherence between counter electrode and the FTO substrate. Our findings, thereby, offer the possibility to engineer and optimize the energy levels of CE in an effort to develop a high-performing DSSC counter electrode.

Sb2S3 entrenched MWCNT composite as a low-cost Pt-free counter electrode for dye-sensitized solar cell and a viewpoint for a photo-powered energy system

The current research interest is to use Sb2S3 entrenched Multi-Walled Carbon Nanotubes (MWCNT) composite as Pt-free counter electrode in dye-sensitized solar cells (DSSCs) and also to test its usage as a supercapacitor. Hence here, Sb2S3 nanorods with different concentrations of MWCNT have been synthesized by facile microwave irradiation technique and are used as a counter electrode in Pt-free DSSCs and also tested for supercapacitance. Crystalline structure, shape, and quantum states have been elucidated using XRD, TEM, and XPS spectra, respectively. Among all, Sb2S3/CNT30 composite counter electrode delivers the highest Power Conversion Efficiency (PCE) of 5.02% with a short circuit current (JSC) of 12.68 mA cm−2 and open-circuit voltage (VOC) of 0.68 V. The improvement observed is due to the lower peak-to-peak separation (Epp), higher exchange current density (J0) and lower charge transfer resistance (RCT). The obtained PCE is compared with the standard Pt-based counter electrode (PCE~5.8%) and discussed. This composite is also found to be a suitable material for the supercapacitor. Among the electrodes, Sb2S3/CNT100 exhibits the highest specific capacity of 228 C g−1 with 1 Ag−1 with the capacitive retention of ~92.5% over 1000 charge-discharge cycles, which also reveals its ability for energy storage. The excellent capacitive and photovoltaic output highlights the promise of Sb2S3/MWCNT for photo-supercapacitor devices.

Nickel foam supported Pt as highly flexible counter electrode of dye-sensitized solar cells

In this paper, Pt nanoparticles are deposited on nickel foam by the mild displacement reaction occurring at room temperature. Thus prepared nickel foam supported Pt is used as efficient and highly flexible counter electrode of dye-sensitized solar cells (DSSCs), the performance of which can be enhanced by simply prolonging the reaction time. The results denote that when the reaction time is just 40 min, the nickel foam supported Pt has exhibited better catalytic activities than the commonly used polyethylene naphthalate polymers supported Pt. The deposition of Pt is investigated by the scanning electron microscopy, X-ray photoelectron spectroscopy, energy dispersive spectroscopy and UV–Vis spectra, and the catalytic activities of fabricated flexible Pt counter electrode are verified by electrochemical impedance spectra and cyclic voltammetry curves. The approach proposed here is facile and can be used for the large scale fabrication of efficient flexible counter electrode in DSSCs.